PURPOSE: To recognize the removal of the pawl of a rotary hook, that is, an excessive running-out of a plunger, when the housing of a tensioner is inserted and fixed.

CONSTITUTION: Even though a pawl 13a is removed from a locked pin 18a for some cause, when a tensioner 1 is inserted to the installing hole 40 of a cylinder head 4, the pawl 13a of a rotary hook 13 rotated downward by the gravity is provided in a groove 46. Since the pawl 13a is hit and engaged to the stopper vertical wall surface 46c of the groove 46, the tensioner 1 cannot be inserted any more, and a housing 10 cannot be fixed to a regular position. As a result, an abnormal insertion is recognized by a worker and the like.